LibWeb: Parse widows CSS property

Author: https://github.com/Calme1709
Commit: c4d6deb5c7
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/6313
Reviewed-by: https://github.com/AtkinsSJ ✅

Libraries/LibWeb/CSS/Properties.json

@@ -3660,6 +3660,15 @@
       "discard-inner"
     ]
   },
+  "widows": {
+    "animation-type": "by-computed-value",
+    "inherited": true,
+    "initial": "2",
+    "valid-types": [
+      "integer [1,∞]"
+    ],
+    "__comment": "FIXME: We don't implement this property any further than compute time"
+  },
   "width": {
     "animation-type": "by-computed-value",
     "inherited": false,